The Impossible Crime
by Prisoner of Azkaban711
Summary: What if there had been a set of detectives to properly analyse the crime scene when Sirius Black "killed" Peter Pettigrew? Would the outcome have been different? Mac, Flack and Jo head the investigations into the Potters' deaths and the truth about their betrayal. But could some deep secrets be brought back to the surface when things get complicated? (rated T because I'm paranoid)
1. One Confusing Crime Scene

Author's note: This is an idea I had ages ago, but have only just got around to writing because my friends and I had a challenge to post before midnight ages ago and I only made it with twenty minutes to spare. I have now re-read this chapter and corrected any mistakes I may have made and anything I might have forgotten in my struggle to finish before the deadline. Please enjoy - we're going to introduce the crime scenes first, focusing on the CSIs, then the Harry Potter part later on :)

Disclaimer: I don't own either Harry Potter or CSI NY.

Chapter 1: 

Early morning sunlight reflected off of the plain glass windows of shops lining an ordinary street in London. The early morning shoppers had begun to crowd the street, exchanging pleasantries and commenting on the latest fashions that lined the shop windows or the quality of the bakery's fresh loaves. Everything was perfectly normal until-

"TRAITOR!"

The cry rang out through the tightly packed street. From every direction, people turned to stare at the two men, dressed strangely in dark robes and cloaks. When compared to the coats and trousers of most of the people in the street with them, the pair looked highly out of place.

The two looked exact opposites of each other, in both size and expression. One, a tall lean man with a crop of shoulder length black hair had backed the other, a rather short, plump man with short mousy curls into the corner of the street. His expression was livid as he threatened the cowering man before him, pointing what appeared to be a wooden stick to his throat.

But then, the shorter man raised his voice:

"First Lily and James and now me! What did I ever do to you Sirius?"

"WHAT DID YOU DO?" the other man, Sirius roared. "DO YOU NEED ME TO SPELL IT OUT FOR YOU?" pushing the other man further against the wall. "YOU ALWAYS WERE A COWARD PETER!"

"I did nothing Sirius," Peter squeaked, though still loud enough for the growing crowd to hear. "It was you! How could you?"

The rest happened too quickly for anyone to react. Sirius let out a growl of anger and

a second later the air was filled with dust... shouts... rubble.

Sirius turned on the spot, trying to survey the scene before him but only managing to catch glimpses of the terrified crowd. His confusion then dissipated as he realised what had happened.

Among the cries of the injured crowd, the laughter could be heard, echoing from his throat.

He heard a dozen cracks and felt the pressure of two pairs of hands on his arms, he allowed himself to be held in place, not having enough energy to try and stop them. Tricked. All of them. By Peter Pettigrew, whom no one would have suspected of anything. Sirius continued to laugh at how stupid they had all been to not realise...And to think that he had suspected Remus...

As the dust began to settle at his feet, Sirius could see the scene unfolding around them. He stood in a crater, surrounded by Magical Law Enforcement Squad, recognisable by their Ministry uniforms. The pavement and road had been blown to pieces, cracking the sewers open and causing the stench of sewage to mingle with the smell of blood in the air.

Before him lay a bundle of rags, formerly robes, covered with blood and dirt. To anyone else, this may have caused them to sober immediately, but Sirius just continued to laugh at the simplicity of Peter's plan, and yet how brilliantly he had had them all fooled.

Further from him, he saw the bodies of Muggles lying on the floor with others standing over them, crying, shouting or trying to offer whatever help they could.

Before he could take a full look and really take in the gravity of what had happened, a short, slightly portly man stepped in front of him. He looked slightly ill, taking nervous glances at the people around them and occasionally at the pile of clothes to Sirius' right.

"Sirius Black," he said, sounding as though keeping composed was taking all of his energy. "I, Cornelius Fudge, arrest you for the murders of Wizard, Peter Pettigrew and twelve muggles. There will be no need for you to say anything."

And with that, Fudge indicated to the two wizards holding Sirius to take him away, with a nod of his head. He then turned to another and said:

"You know what to do; take statements then wipe their memories. They shouldn't have to remember this."

Sirius took one last look at the crowd of muggles and the open sewer before the whole scene vanished.

That was when the sound of the sirens began to reverberate through the polluted air.

OoOoO

"Mac!"

"What have we got, Flack?" asked Mac Taylor as he ducked under the yellow tape barrier that had already been put up in order to keep the scene from the prying eyes of the public. He turned to Don Flack as they began to walk down towards the centre of the street.

"Witness called it in whilst it was happening; two men over on that side of the street shouting at the top of their voices, crowd gathered around the edge watching. The explosion ripped the street apart, taking the sewer with it," Flack explained to Mac from the notes scrawled hastily on his pad.

"And where is our witness now?" Mac asked as they passed a few other cops headed in the direction they had previously come.

"Dead. Part of the front of the crowd that got caught in the explosion. We've got thirteen deceased in total, but only twelve bodies," Flack finished, turning to Mac as they came to a stop in front of Hawkes who stood as they approached. Mac's face turned to one of confusion.

"I might be able to help with that," he said moving to join them. "Though I've got queries about it too. There is a pile of blood splattered clothes on the floor with the only recognisable body part being the right index finger on the floor. But other than that there is no blood splatter on the walls or floor or anywhere else to be honest. No evidence to show there was anyone stood there at all. It just doesn't seem to fit with a typical explosion that you usually find. All the other bodies have minimal trace, mainly hit by rubble from the street. But I'm not sure what was used here," Hawkes concluded as Mac looked at the variety of surfaces that were covered in dust and shards of the shattered street.

"What about the man they caught?" Mac asked the cop and the former pathologist. "With this many witnesses surely there is no way they can't convict him?"

"The guy's pleading that he's innocent. He was taken away by a specialist group right after the explosion. Our guys arrived on the scene about ten minutes later so we haven't been able to hear his side of the tale yet, but it definitely seems to be worth investigating, Mac."

"Alright" Mac responded, clearing surmising that that was all the information he was going to get out of his detective. "Sheldon, get the bodies to Sid; see if he can make anything else out that you might have missed."

"Yes Boss," Hawkes replied, jogging over to the team moving the stretchers into the van.

As Hawkes left, Lindsay Messer walked over to the head of the crime lab, camera in hand.

"Mac- I've marked up and photographed the initial findings, but it's going to take a while to sort through all this to find what's really important here," she told him, with a slight grimace.

"Take as long as you need Lindsay and I'll find some extra people to try and help you - sounds as though you're going to need them," Mac replied to her. She nodded and moved away towards the crater in the street.

Once Lindsay had gone, Mac continued to talk to Flack-

"Flack, come with me, we're going to find out more about the man who blew these people away."

A/N: Cue 'Baba O'Reily' by The Who. Please review- It is much appreciated :) Thanks!


	2. An Extra Conundrum

Author's note: Hi again guys! Sorry I haven't posted in so long - I've been kept really busy. If you read this before 21st February 2015 then you might want to go back and re-read the previous chapter as I have made some changes and added Lindsay into it in order to spread the team fairly evenly across the two crime scenes. Also, just to say that this story uses the season 9 cast because I'm a huge fan of Flack and Lovato :) So enjoy the next chapter!

Disclaimer: I don't own either Harry Potter or CSI NY.

Chapter 2: 

Jo Danville stood looking up at the remains of what she imagined had once been a very handsome looking home. The roof, now caved in on one side, had fallen in pieces across the small garden, along with half an ivy covered wall. The house now looked derelict; as though no one had set foot there in a long while.

"Such a shame," she sighed to no one in particular as she stepped across the threshold, her camera held tightly in her left hand.

As she entered the hallway, she saw Sid leaning over a body lying, crumpled at the base of the stairs. She sighed again as she saw that the man looked barely older than twenty.

"Anything yet?" Jo asked the pathologist, leaning forward to take a picture of the man's face. Round glasses sat over his eyes, which were still open, making Jo shudder.

"Well," Sid replied, sitting back on the balls of his feet, "No, not really. No surface wounds that I can see including no defensive wounds or bruising. There is no sign of asphyxia going by his eyes and throat... I'll have to see what the toxicology report brings back to see whether it was poison that killed the poor guy. If it was just him and the situation was a little less... _suspicious_, I would say maybe some sort of blood clot, but given the circumstances, we're definitely looking at murder." He finished and stood up, looking at Jo.

"Is the other body upstairs?" Jo asked as Sid picked up his small bag of tools.

"Yes, I'm just going up to look," Sid replied. He stepped around the man when two other men came to remove the body from the scene. "After you," he said courteously, motioning for Jo to go upstairs.

Jo smiled at him and mounted the carpeted staircase, climbing to the second floor. As she rounded the corner, she almost walked straight into Jamie Lovato, who was walking quickly down the corridor.

"Oh!" she exclaimed as she quickly stopped in order to prevent the collision between them. "Oh Jo, I thought I heard you. I was just coming down to get you," Jamie said, holding her notebook up. "Do you want information?"

"I'll take anything you've got," Jo replied quickly, walking with Lovato to the room at the end of the hallway.

"Okay," Lovato began. "The house belongs to James and Lily Potter, and judging by the pictures around the place, they're our victims as well. James Potter was found downstairs, no wounds to talk of, but I assume Sid told you that already. Lily Potter was found in this room here-"

They came to a stop at the door to what looked like a small child's nursery. A cot lay at the end of the room, a mobile made up of what looked like some sort of mythical creatures hung over it. However, the room was open to the chilly November air as this is where the roof had been blasted open by an unknown force.

Rubble lay all over the floor and surfaces, making small piles around the woman laid on her front before the cot. Flaming red hair obscured half her face, but her green eyes were still visible under the curtain of crimson.

Jo took several photos of the scene as Jamie continued:

"Initial findings said that she's been moved, but probably from a slightly different position in the room. Again, no obvious cause of death..." she trailed off, with not much more information to give. "Something isn't right here. I mean what could have done that to the roof?" she asked pointing up at the cloudy sky.

"I've no idea," replied Jo, curiosity flowing through her at their baffling crime scene. Stepping over a small rubble pile, she took a few more photos of the collapsed roof and headed back to Sid who was now packing up the last of his materials.

"Same as her husband," he summarised. "No obvious cause of death, not even a scratch. I'll have to see what I can find out with the autopsies but it's as though they just dropped dead." Sid was clearly as clueless as the rest of them.

Jo shook her head, a perplexed look spreading across her face. What could possibly have killed these two people and not left any mark on them?

She was broken out of her contemplation, by Danny Messer who called her over to the lowest point in the cracked wall where the roof and bricks had become separated from it. His kit was spread across the base of the wall, used testing equipment sat in a small pile to the left of him.

"Hey Danny, what have you got?" Jo asked him as Lovato walked over to join them.

"About as much as anyone else it seems," he replied exasperatedly. "I've tested for as many possible explosives as I can but there isn't any residue. Like, at all-" he motioned around the edge of the shattered structure. "There were only a few prints that I could find... I just don't know." He ran his hand through his hair and looked at Jo.

She put her hand on his shoulder before saying: "Don't worry Danny. I think this one has got us all confused, but we'll solve it. We always do."

He smiled at her continued optimism, even though this case really did look a step too far.

"Hey Jo," Lovato said, stepping away from her and Danny, "this picture on the floor..."

A photo frame, which looked like it had fallen from the shelf above it, was laid face down on the carpet. Carefully, Jo slipped on a plastic glove and, after taking a picture, picked up the photograph.

The glass in the frame was cracked slightly in one corner from it's fall, the thin lines had spread across the middle of the glass. The picture showed five people all smiling at the camera at what looked, from their clothes, like a wedding.

"There are our vics." Lovato pointed to the man and woman, arm in arm at the front of the image, beaming for the photographer. Behind them stood three other men, all laughing at an forgotten joke. "We need to find these guys. They could know something that will help our case. Enemies, recent arguments between the Potters and other people..." Lovato finished.

"I agree," said Danny, who bagged the picture in an evidence bag and sealed it shut. "Let's get this stuff back to the lab and see if we can find these guys' identities."

Jo took a few last photos of items that had been marked with the small, yellow number cards by Danny and followed Jamie out of the room and back into the entrance hall, where James Potter's body no longer lay.

"This makes no sense," muttered Jo as she left the scene, ducking under the yellow crime scene tape.

OoOoO

"Mac!"

Mac turned at the sound of Jo Danville's voice coming from further down the hall. He stopped walking and allowed her to catch up with him before continuing on his path to his office.

They entered through the glass door and Mac took his chair behind the slightly cluttered desk, where all his current case notes were piled up. Carefully, he placed a cup of coffee in a section of desk that had nothing on it and looked at the CSI who had taken the chair opposite.

"You will never believe the lack of evidence at the crime scene we worked this morning Mac. I don't think I've ever been to a crime where Sid couldn't at least give a educated guess on what killed the victim, but he was clueless today!" Jo sighed and looked into the file she was holding and passed Mac a sheet with pictures of both Lily and James Potter's bodies. "There is nothing! Absolutely nothing."

Mac looked at the pictures in his hand and then pulled out his own case file of the scene he and Flack had worked earlier. He gave Jo a picture of the bloody clothes pile that they had brought back to analyse.

"I think you'd be surprised - there seems to be a fair amount of confusion going around at the moment. We're trying to get a warrant for this guy-" He clicked a button on his remote that brought up the picture of Sirius Black onto the television screen to his right. "-to bring him in for questioning, but the people holding him are being pretty stubborn about letting him into our custody. What's wrong Jo?" he asked suddenly as he watched Jo's expression change when she looked at the screen.

"He was in the picture," she said, beginning to rifle through the sheets in her file and found the one of the cracked photo frame. "There. That's him, isn't it?"

Mac looked at the image in Jo's hand and back at the screen to confirm that the man was in fact the same. He turned back to her and said:

"I think we've just worked out the first thing in our investigations - these cases are connected."

A/N: Well, we've introduced the scenes now and they know that Sirius is connected to both of them. Also I know that Harry Potter is set in the UK and CSI in America, but for the purposes of this can we just leave that distance out of it - I don't want to take the CSI team away from their labs and stuff so just bear that in mind!

Please review :) I appreciate your feedback.


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